Multiple channels of optical information may be carried within a single optical signal similar to multiple channels of television being transmitted to a consumer's home through a single cable TV signal. The multiple signals within the optical signal may be broadcast through a technique called dense wavelength division multiplexing which interweaves all the channels into a single photo optic signal. The International Telecommunications Union established a frequency grid spacing of one hundred GigaHertz (i.e. about eight tenths of a nanometer between adjacent channels of optical information). For example, five adjacent optical channels may be optical wavelengths of 1550.12 nanometers (nm), 1549.32 nm, 1548.51 nm. 1547.72 nm, and 1546.92 nm. Thus, bandwidth of each channel is confined to a very narrow band of wavelengths, such as 1549.12 nm to 1549.52 nm (1549.32 nm+/−0.2 nm) in order to prevent a fist channel overlapping into an adjacent channel and distorting the information in both channels.
Acousto-optic technologies may use an acoustic wave to manipulate a photo optic signal traveling through an optical fiber. The acoustic wave may be used to manipulate a narrow band of wavelengths within the photo optic signal.
Several related acousto-optic sideband generating technologies have disadvantages that make those technologies commercially impractical. A first acousto-optic sideband generating technology and a second acousto-optic sideband generating technology generate longitudinal acoustic waves that induce accordion like ripples on a reduced diameter optical fiber containing a fiber Bragg grating. The optical fiber has a core that contains a fiber Bragg grating and a cladding that surrounds the core positioned in the center of the cladding. The diameter of the optical fiber is reduced to magnify the acoustic waves effect of vibrating the periodic gratings inscribed in the fiber Bragg grating. The vibrating fiber Bragg grating may be tuned to manipulate a particular band of wavelengths within the photo optic signal. In these technologies, without a reduced diameter optical fiber, a stronger amplitude acoustic wave is needed to achieve the desired tuning of the periodic gratings. If the vibration from the acoustic wave becomes too strong, then damage may occur to the optical fiber, especially where the optical fiber is being clamped in place.